This application relates to bullets or projectiles that are part of ammunition cartridges typically used for rapid fire guns mounted on military vehicles such armored personnel carriers or the U.S. Army's High Mobility Multipurpose Vehicle (HMMV). The design for a projectile disclosed herein could also be adapted to larger weapons such as the main gun on a tank or smaller weapons such as hand held firearms carried by infantrymen. More specifically, the invention relates to projectiles which have an outer surface comprised of a plastic such as polytetrafluoroethylene, commonly referred to as teflon.
One of the advantages of a teflon coated projectile is the relatively low friction between the projectile and the gun barrel from which it is fired. Since the inner diametrical surface, or land, of a rifled gun barrel is smaller than the outer diameter of the projectile, friction between the projectile and the gun barrel is a significant factor in firing the gun. The low friction makes possible higher projectile speeds and reduces heat build up in the gun barrel during repeated firing of the gun. Consequently, the gun barrel has less tendency to sag or distort as a result of the gun being continuously fired. Additionally, a teflon coated projectile does not deposit lead or other metal from the projectile on the inner diameter of the barrel, thereby avoiding fouling of the gun. Such a projectile has been described in the U.S. Pat. No. 4,328,750 to Oberg et al.
My invention is a projectile having a metal or ceramic core surrounded by a plastic jacket, the invention having the same advantages as those referred to above for the teflon coated projectile as well as other advantages. The jacket of my projectile is made from a flexible, resilient material such as teflon so that the jacket takes more or essentially all of the deformation of the projectile and barrel when the projectile is fired. The jacket of my projectile thus protects a lead or ceramic core from deformation or damage and reduces wear on the barrel. In addition, when my projectile leaves the barrel, the ridges on the projectile formed by the rifling grooves of the barrel either reduce in size or disappear altogether. The projectile consequently has a smoother, more aerodynamically efficient surface during flight and has a more accurately predictable flight path.
My design for a plastic jacketed projectile is relatively easy to manufacture. It is contemplated that the core can be cast or stamped by a relatively small press of, say, an eight ton capacity. The core can then have the plastic jacket injection molded around it preferably using a thermosetting resin, although a castable urethane plastic can also be used. The core of the projectile can be made of various weights, centers of gravity or shapes without changing the overall configuration of the projectile.
The flexibility of the plastic jacket permits my projectile to travel through a gun barrel with less driving force than a conventional projectile of similar size and weight. Consequently, less propellant is needed for a given round of ammunition and a smaller, lighter propellant compartment can be utilized so as to reduce the overall size and weight of the round. Therefore the round will not only be less expensive but the logistical cost of getting the round to soldiers in the field will be reduced. From a tactical standpoint, a soldier or military vehicle will be able to carry more rounds with my projectile than conventional rounds, whereby my projectile is advantageous in a battlefield scenario.